臺灣博碩士論文加值系統

摘 要
本文係針對具流體承載及週期支撐的無限長樑在受到簡諧移動外力作用下之振動及聲能響應特性進行分析。文中提出了一種新的分析法，稱為波數-簡諧(Wavenumber-harmonic)法，乃藉由富立葉(Fourier)轉換及配合整體波數響應的關係而表示成一組宏觀的級數解析解，此級數解不僅可完整的表示因週期支撐而顯現的各種振動及聲能特性，更別於傳統上需將樑切成各單一次結構而受限於兩個次結構間邊界條件及相位差的 "韃?簡諧" (Space-harmonic)法。另文中亦說明此法與流體承載的易結合性及便於計算不同流體承載及週期支撐的無限長樑其聲能響應值。最後，對於不同的Bernoulli-Euler或Timoshenko樑及不同的週期彈性支撐或彈性基底等特性，亦藉由數值分析的結果來討論此法在各種外力移動速度、不同流體承載及彈性支撐作用下對樑振動量及聲能響應的影響。

ABSTRACT
The vibro-acoustic response of an infinite, fluid-loaded, periodically supported beam under a convected harmonic loading has been investigated. A new method, named wavenumber harmonic analysis, is proposed to formulate the vibro-acoustic model. This method involves the use of spatial Fourier transform, and then the associated wavenumber response is expressed in a series form. This series represents wave components of the flexural motion that characterizes the vibro-acoustic behavior of the periodic supported beam. This approach differs from the space-harmonic analysis, which describes the beam motion in a spatial domain. Instead of considering the dynamics of a single substructure as the space harmonic method, the proposed formulism does not require the information of the phase relation between two substructures. Furthermore, the fluid loading effect is easy to be incorporated and the sound power radiated from a fluid-loaded, infinite, periodically supported beam subjected to a moving load can be calculated conveniently. Numerical examples including vibro-acoustic analysis of fluid-loaded, periodically supported Bernoulli-Euler and Timoshenko beams, and beams on elastic foundation are demonstrated to illustrate the theoretical predictions.

Cover
ACKNOWLEDGE
ABSTRACT (CHINESE)
ABSTRACT (ENGLISH)
CONTENTS
LIST OF TABLES
LIST OF FIGURES
NOMENCLATURE
CHAPTER
1. INTRODUCTION
1.1 Motivation and objective
1.2 Literature review
1.3 Dissertation outline
2. VIBRATION ANALYSIS OF A PERIODICALLY SPRING SUPPORTED BERNOULLI-EULER BEAM
2.1 Formulation
2.2 Analysis parameters
2.3 Numerical results and discussion
2.4 Conclusion
3. VIBRO-ACOUSTIC ANALYSIS OF A PERIODICALLY SPRING-SUPPORTED TIMOSHENKO BEAM
3.1 Formulation
3.2 Analysis parameters
3.3 Numerical results and discussion
3.4 Conclusion
4. A BEAM ON AN ELASTIC FOUNDATION
4.1 Equation of motion of a Bemoulli-Euler beam on an elastic foundation
4.2 Equation of motion of a Timoshenko beam on an elastic foundation
4.3 Analysis parameters
4.4 Numerical results and discussion
4.5 Conclusion
5. CONCLUSION
5.1 Conclusion
5.2 Future work
REFERENCES
PUBLICATIONS
VITA

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